HI,
How are you? One of prednisone's side effects may indeed include difficulty falling asleep or staying asleep. Once the medicine is out of the system, the symptoms usually resolve. The duration may last from 1-2 days and the time it takes may also depend on a variety of factors such as the condition present, how well you tolerate the drug or the medical history of the patient. There are other symptoms associated with this medicine such as those found in this link: http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601102.html#side-effects.
Take care and do keep us posted.